SOLUTION: A car averaged 40 mph for part of a trip and 50 mph for the remainer. If the 5-hour trip covered 210 miles, for how long did the car average 40 mph?
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Question 408008: A car averaged 40 mph for part of a trip and 50 mph for the remainer. If the 5-hour trip covered 210 miles, for how long did the car average 40 mph? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! A car averaged 40 mph for part of a trip and 50 mph for the remainder.
If the 5-hour trip covered 210 miles, for how long did the car average 40 mph?
:
Let t = time at 40 mph
then, since the total time was 5 hrs:
(5-t) = time at 50 mph
:
Write a dist equation: Dist = speed * time
40t + 50(5-t) = 210
40t + 250 - 50t = 210
40t - 50t = 210 - 250
-10t = -40
t =
t = +4 hrs at 40 mph
:
:
Check the solution by finding the dist at each speed (5-4 = 1 hr at 50mph)
4(40) + 1(50) =
160 + 50 = 210
